首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   3464篇
  免费   271篇
  国内免费   24篇
耳鼻咽喉   13篇
儿科学   106篇
妇产科学   120篇
基础医学   462篇
口腔科学   33篇
临床医学   418篇
内科学   591篇
皮肤病学   44篇
神经病学   392篇
特种医学   56篇
外科学   448篇
综合类   35篇
一般理论   5篇
预防医学   526篇
眼科学   68篇
药学   233篇
中国医学   1篇
肿瘤学   208篇
  2023年   34篇
  2022年   30篇
  2021年   87篇
  2020年   51篇
  2019年   80篇
  2018年   129篇
  2017年   72篇
  2016年   66篇
  2015年   62篇
  2014年   125篇
  2013年   195篇
  2012年   219篇
  2011年   220篇
  2010年   115篇
  2009年   103篇
  2008年   205篇
  2007年   242篇
  2006年   213篇
  2005年   244篇
  2004年   191篇
  2003年   202篇
  2002年   169篇
  2001年   42篇
  2000年   26篇
  1999年   43篇
  1998年   32篇
  1997年   28篇
  1996年   32篇
  1995年   36篇
  1994年   36篇
  1993年   31篇
  1992年   28篇
  1991年   21篇
  1990年   12篇
  1989年   10篇
  1988年   21篇
  1987年   15篇
  1986年   20篇
  1985年   18篇
  1984年   22篇
  1983年   19篇
  1982年   11篇
  1981年   15篇
  1980年   16篇
  1979年   23篇
  1978年   15篇
  1976年   10篇
  1975年   15篇
  1972年   15篇
  1971年   10篇
排序方式: 共有3759条查询结果,搜索用时 15 毫秒
91.

Background

Ethnic variation in the occurrence of type 2 diabetes, complications, mortality, and health behaviours has been reported. The current research examined patterns of health-related outcomes by country of birth in people with diabetes aged 45 years and over in New South Wales, Australia.

Methods

This study was based on the baseline data of 266,848 participants aged 45 years and over from “The Sax Institute’s 45 and Up Study” (2006–2009), NSW; Australia’s most populous state. Health-related factors including self-rated overall health, Quality of Life (QoL), eyesight, subjective memory complaint, hearing loss, psychological distress and functional limitation were examined according to country of birth among 23,112 people with type 2 diabetes. Logistic regression modelling was used to compare the odds of poor outcomes between Australian-born and overseas-born participants, adjusting for potential confounding and mediating variables. Both age-sex and fully adjusted odds ratios (aORs) are reported.

Results

Nearly half of the people with diabetes in the sample reported hearing loss and high levels of functional limitations, a third reported poor overall health. Compared to people with diabetes born in Australia, people born in South East Europe, North Africa, the Middle East had significantly greater odds of poor outcomes across the majority of examined health-related factors, with the largest odds observed in the elevated level of psychological distress outcome (aOR = 3.4 in North African and the Middle East group). Higher aORs of poor overall health, QoL, memory problems and poor eyesight, and lower aORs for hearing loss, were also found among those born in the Asian countries.

Conclusions

The results demonstrated significant ethnic disparity in the prevalence of health-related outcomes. These findings provide important context for the formulation of culturally sensitive secondary prevention strategies.  相似文献   
92.
Ion-channel gene defects are associated with a range of paroxysmal disorders, including several monogenic epilepsy syndromes. Two autosomal dominant disorders present in the first year of life: benign familial neonatal seizures, which is associated with potassium-channel gene defects; and benign familial infantile seizures, for which no genes have been identified. Here, we describe a clinically intermediate variant, benign familial neonatal-infantile seizures, with mutations in the sodium-channel subunit gene SCN2A. This clinico-molecular correlation defines a new benign familial epilepsy syndrome beginning in early infancy, an age at which seizure disorders frequently have a sombre prognosis.  相似文献   
93.
94.
95.
96.
Rabies virus (RV) nucleoprotein (N) tightly encapsidates the genomic and antigenomic RNA of RV to form the viral ribonucleoprotein (RNP) complex. Antigens, such as N, presented in a highly organized structure are sufficient and even desirable to activate B cells to proliferate and produce antibodies. In addition to activating B cells to proliferate, it has been shown that RV N in the RNP complex induces potent T helper cell responses resulting in long-lasting and strong humoral immune responses against RV. The possibility to systematically incorporate foreign genes into the genome of RV and produce a recombinant virus allows us to examine whether the immunogenicity of foreign antigens can be enhanced by incorporation into the RV RNP structure. To test this hypothesis we constructed a recombinant RV expressing a RV N-GFP fusion protein. The chimeric N-GFP fusion protein was efficiently expressed and incorporated into RV RNP and virions. Moreover, the recombinant RNP induces a strong humoral immune response against GFP in mice. In contrast, mice inoculated with GFP alone or a combination of wild-type RV RNPs and GFP did not trigger any GFP-specific humoral responses using the same immunization schedule. These data indicate the usefulness of RV-based vectors as killed vaccines against other infectious diseases.  相似文献   
97.
Attenuated tissue culture-adapted and natural street rabies virus (RV) strains differ greatly in their neuroinvasiveness. To identify the elements responsible for the ability of an RV to enter the CNS from a peripheral site and to cause lethal neurological disease, we constructed a full-length cDNA clone of silver-haired bat-associated RV (SHBRV) strain 18 and exchanged the genes encoding RV proteins and genomic sequences of this highly neuroinvasive RV strain with those of a highly attenuated nonneuroinvasive RV vaccine strain (SN0). Analysis of the recombinant RV (SB0), which was recovered from SHBRV-18 cDNA, indicated that this RV is phenotypically indistinguishable from WT SHBRV-18. Characterization of the chimeric viruses revealed that in addition to the RV glycoprotein, which plays a predominant role in the ability of an RV to invade the CNS from a peripheral site, viral elements such as the trailer sequence, the RV polymerase, and the pseudogene contribute to RV neuroinvasiveness. Analyses also revealed that neuroinvasiveness of an RV correlates inversely with the time necessary for internalization of RV virions and with the capacity of the virus to grow in neuroblastoma cells.  相似文献   
98.
Ghrelin is a recently identified growth hormone (GH) secretogogue whose administration not only induces GH release but also stimulates food intake, increases adiposity, and reduces fat utilization in mice. The effect on food intake appears to be independent of GH release and instead due to direct activation of orexigenic neurons in the arcuate nucleus of the hypothalamus. The effects of ghrelin administration on food intake have led to the suggestion that inhibitors of endogenous ghrelin could be useful in curbing appetite and combating obesity. To further study the role of endogenous ghrelin in appetite and body weight regulation, we generated ghrelin-deficient (ghrl(-/-)) mice, in which the ghrelin gene was precisely replaced with a lacZ reporter gene. ghrl(-/-) mice were viable and exhibited normal growth rates as well as normal spontaneous food intake patterns, normal basal levels of hypothalamic orexigenic and anorexigenic neuropeptides, and no impairment of reflexive hyperphagia after fasting. These results indicate that endogenous ghrelin is not an essential regulator of food intake and has, at most, a redundant role in the regulation of appetite. However, analyses of ghrl(-/-) mice demonstrate that endogenous ghrelin plays a prominent role in determining the type of metabolic substrate (i.e., fat vs. carbohydrate) that is used for maintenance of energy balance, particularly under conditions of high fat intake.  相似文献   
99.
Background  Little is known about how Latinos with post-traumatic stress disorder (PTSD) understand their illness and their preferences for mental health treatment. Objective  To understand the illness beliefs and treatment preferences of Latino immigrants with PTSD. Design  Semi-structured, face-to-face interviews. Participants  Sixty foreign-born, Latino adults recruited from five primary care centers in New York and New Jersey and screened for PTSD. Approach  Content analytic methods identified common themes, their range, and most frequent or typical responses. Results  Participants identified their primary feelings as sadness, anxiety, nervousness, and fear. The most common feeling was “sad” (triste). Other words frequently volunteered were “angry” (enojada), “nervous” (nerviosa), and “scared” (miedo). Participants viewed their PTSD as impairing health and functioning. They ascribed their somatic symptoms and their general medical problems to the “stress” from the trauma and its consequences on their lives. The most common reason participants volunteered for their work and school functioning being impaired was their poor concentration, often due to intrusive thoughts. Most expressed their desire to receive mental health treatment, to receive it within their primary care center, and preferred psychotherapy over psychotropic medications. Among participants who did not report wanting treatment, most said it was because the trauma was “in the past.” Conclusions  Clinicians may consider enquiring about PTSD in Latino patients who report feeling sad, anxious, nervous, or fearful. Our study suggests topics clinicians may include in the psychoeducation of patients with PTSD.  相似文献   
100.

Background

Acid reflux has been associated with poor outcomes following lung transplantation. Unlike surgical fundoplication, the role of noninvasive, pharmacologic acid suppression remains uncertain.

Aims

To assess the relationship between post-transplant acid suppression with proton pump inhibitors (PPI) or histamine-2 receptor antagonists (H2RA) and onset of early allograft injury or chronic rejection following lung transplantation.

Methods

This was a retrospective cohort study of lung transplant recipients at a tertiary center in 2007–2014. Patients with pre-transplant antireflux surgery were excluded. Time-to-event analysis using the Cox proportional hazards model was applied to assess acid suppression therapy and onset of acute or chronic rejection, defined histologically and clinically. Subgroup analyses were performed to assess PPI versus H2RA use.

Results

A total of 188 subjects (60% men, mean age 54, follow-up 554 person-years) met inclusion criteria. During follow-up, 115 subjects (61.5%) developed rejection, with all-cause mortality of 27.6%. On univariate analyses, acid suppression and BMI, but not other patient demographics, were associated with rejection. The Kaplan–Meier curve demonstrated decreased rejection with use of acid suppression therapy (log-rank p = 0.03). On multivariate analyses, acid suppression (HR 0.39, p = 0.04) and lower BMI (HR 0.67, p = 0.04) were independently predicted against rejection. Subgroup analyses demonstrated that persistent PPI use was more protective than H2RA or no antireflux medications.

Conclusions

Post-lung transplant exposure to persistent PPI therapy results in the greatest protection against rejection in lung transplant recipients, independent of other clinical predictors including BMI, suggesting that PPI may have antireflux or anti-inflammatory effects in enhancing allograft protection.
  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号